[推荐]集合万用表的使用方法...

<div class="Section1" style="LAYOUT-GRID:  15.6pt none;"><span style="FONT-SIZE: 16pt; FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;"><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 15.75pt; mso-char-indent-count: 1.5;"><font size="3"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">&nbsp; 万用表的三个基本功能是测量电阻、电压、电流，所以老前辈们叫它三用表。</span><span style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;"><br/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">现在的万用表添加了好多新功能，尤其是数字式万用表，如测量电容值，三极管放大倍数，二极管压降等，更有一种会说话的数字万用表，能把测量结果用语言播报出来。（其实不是很难，</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">Bitbaby</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">曾有一度很想用单片机和语音电路做一个，<span style="COLOR: red;">但语言型的阿坤还没有见过哈！</span>）</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;"><p></p></span></font></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 15.75pt; mso-char-indent-count: 1.5;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;"><font size="3">&nbsp; 万用表是测量电阻、电压、电流和音频电平等的仪表。</font></span><span lang="EN-US"><font face="Times New Roman">&nbsp;&nbsp;&nbsp;</font></span></p></span><span lang="EN-US"><font face="Times New Roman">&nbsp;&nbsp;&nbsp;</font></span></div><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US" style="COLOR: red;"><font face="Times New Roman">a</font></span><span style="COLOR: red; FONT-FAMILY: 宋体; mso-bidi-font-family: 宋体;">?测电阻?</span><span lang="EN-US" style="COLOR: red;"><font face="Times New Roman"><br/>&nbsp;&nbsp;&nbsp;&nbsp;<p></p></font></span></p><p></p><p></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 31.5pt; mso-char-indent-count: 3.0;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">在测量电阻时，应在标有“Ω”的刻度上看读数</span><span lang="EN-US"><font face="Times New Roman">(</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">由于通过表头的电流与被测电阻不是成正</span><font face="Times New Roman"><br/>&nbsp;&nbsp;</font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">比关系，所以表盘上的电阻标度尺是不均匀的。</span><span lang="EN-US"><font face="Times New Roman">)</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">被测电阻的实际值等于标度尺上的读数乘</span><font face="Times New Roman"><br/>&nbsp;&nbsp;</font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">以旋钮所指的倍数。在测量前，应先将两表笔短接，转动调零电位器，使指针在</span><span lang="EN-US"><font face="Times New Roman">0</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">Ω的位置</span><font face="Times New Roman"><br/>&nbsp;&nbsp;</font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">，然后选择合适的挡位以保证测量的准确。每换一个量限，都要重新调零。另外，电阻的测量，一定要无源及无其它并联支路的情况下进行。</span><span style="FONT-FAMILY: 宋体; mso-bidi-font-family: 宋体;">?</span><span lang="EN-US"><font face="Times New Roman"><br/>&nbsp;&nbsp;&nbsp;</font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 26.25pt; mso-char-indent-count: 2.5;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">电阻</span><span lang="EN-US"><font face="Times New Roman">(</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">或电流</span><span lang="EN-US"><font face="Times New Roman">)</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">测量完毕后，应将转换开关旋至高电压挡位，这是防止误用欧姆表</span><span lang="EN-US"><font face="Times New Roman">(</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">或电流挡</span><span lang="EN-US"><font face="Times New Roman">) </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">测电压的良好习惯。</span><span style="FONT-FAMILY: 宋体; mso-bidi-font-family: 宋体;">?</span><span lang="EN-US"><font face="Times New Roman"><br/>&nbsp;&nbsp;&nbsp;</font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US" style="COLOR: red;"><font face="Times New Roman">b</font></span><span style="COLOR: red; FONT-FAMILY: 宋体; mso-bidi-font-family: 宋体;">?直流电压、电流的测量?</span><span lang="EN-US" style="COLOR: red;"><font face="Times New Roman"><br/>&nbsp;&nbsp;&nbsp;&nbsp;<p></p></font></span></p><p></p><p></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 26.25pt; mso-char-indent-count: 2.5;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">读数时应看“</span><span lang="EN-US"><font face="Times New Roman">DC</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">”或“</span><span lang="EN-US"><font face="Times New Roman">V</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">·</span><span lang="EN-US"><font face="Times New Roman">mA</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">”符号的刻度表，此时旋钮所指的数值即直流</span><font face="Times New Roman"><br/>&nbsp;&nbsp;</font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">电压或电流的最大量限</span><span lang="EN-US"><font face="Times New Roman">(</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">量程</span><span lang="EN-US"><font face="Times New Roman">)</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">。测量前应先估计被测量值的大小，再将转换开关转到适当量</span><font face="Times New Roman"><br/>&nbsp;&nbsp;</font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">限的档位上。按比例可读出测量值的大小。</span><span style="FONT-FAMILY: 宋体; mso-bidi-font-family: 宋体;">?</span><span lang="EN-US"><font face="Times New Roman"><br/>&nbsp;&nbsp;&nbsp;</font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 26.25pt; mso-char-indent-count: 2.5;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">测电路上两点间电压时，红色测试笔应接高电位点，黑色测试笔应接低电位点。</span><span lang="EN-US"><font face="Times New Roman"><br/>&nbsp;&nbsp;&nbsp;</font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 26.25pt; mso-char-indent-count: 2.5;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">测直流电流时，要把电流表串入支路中，所以必须先把被测支路断开。如果没有断开支路就</span><font face="Times New Roman"><br/>&nbsp;&nbsp;</font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">把两支表笔搭到支路的两端点上去，实际上是用电流表去测电压，电表即被烧毁。</span><span lang="EN-US"><font face="Times New Roman"><br/>&nbsp;&nbsp;&nbsp;</font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><span style="COLOR: red;"><span style="mso-spacerun: yes;">&nbsp;</span></span></font></span><span style="COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">用万用表判断电容器质量</span><span lang="EN-US" style="COLOR: red;"><p></p></span></p><p></p><p></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 5.25pt; mso-char-indent-count: .5;"><span lang="EN-US"><span style="mso-spacerun: yes;"><font face="Times New Roman">&nbsp;&nbsp;&nbsp;&nbsp; </font></span></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">视电解电容器容量大小，通常选用万用表的</span><span lang="EN-US"><font face="Times New Roman">R</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">×</span><span lang="EN-US"><font face="Times New Roman">10</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">、</span><span lang="EN-US"><font face="Times New Roman">R</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">×</span><span lang="EN-US"><font face="Times New Roman">100</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">、</span><span lang="EN-US"><font face="Times New Roman">R</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">×</span><span lang="EN-US"><font face="Times New Roman">1K</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">挡进行测试判断。红、黑表笔分别接电容器的负极（每次测试前，需将电容器放电），由表针的偏摆来判断电容器质量。若表针迅速向右摆起，然后慢慢向左退回原位，一般来说电容器是好的。如果表针摆起后不再回转，说明电容器已经击穿。如果表针摆起后逐渐退回到某一位置停位，则说明电容器已经漏电。如果表针摆不起来，说明电容器电解质已经干涸推失去容量。</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><span style="mso-spacerun: yes;"><font face="Times New Roman">&nbsp;&nbsp;&nbsp; </font></span></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">有些漏电的电容器，用上述方法不易准确判断出好坏。当电容器的耐压值大于万用表内电池电压值时，根据电解电容器正向充电时漏电电流小，反向充电时漏电电流大的特点，可采用</span><span lang="EN-US"><font face="Times New Roman">R</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">×</span><span lang="EN-US"><font face="Times New Roman">10K</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">挡，对电容器进行反向充电，观察表针停留处是否稳定（即反向漏电电流是否恒定），由此判断电容器质量，准确度较高。黑表笔接电容器的负极，红表笔接电容器的正极，表针迅速摆起，然后逐渐退至某处停留不动，则说明电容器是好的，凡是表针在某一位置停留不稳或停留后又逐渐慢慢向右移动的电容器已经漏电，不能继续使用了。表针一般停留并稳定在</span><span lang="EN-US"><font face="Times New Roman">50</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">－</span><span lang="EN-US"><font face="Times New Roman">200K</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">刻度范围内。</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><span style="COLOR: red;"><span style="mso-spacerun: yes;">&nbsp;</span></span></font></span><span style="COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">用万用表作为检测工具的集成电路的检测方法</span><span lang="EN-US" style="COLOR: red;"><p></p></span></p><p></p><p></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes;">&nbsp; </span><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;</span></font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">虽说集成电路代换有方，但拆卸毕竟较麻烦。因此，在拆之前应确切判断集成电路是否确实已损坏及损坏的程度，避免盲目拆卸。本文介绍了仅用万用表作为检测工具的不在路和在路检测集成电路的方法和注意事项。文中所述在路检测的四种方法（直流电阻、电压、交流电压和总电流的测量）是业余维修中实用且常用的检测法。这里，也希望大家提供其他实用的（集成电路和元器件）判别检测经验。</span><font face="Times New Roman"><br/>&nbsp;&nbsp;</font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">　　</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><span style="mso-spacerun: yes;"><font face="Times New Roman">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </font></span></span><span style="COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">一、不在路检测</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">　　这种方法是在ＩＣ未焊入电路时进行的，一般情况下可用万用表测量各引脚对应于接地引脚之间的正、反向电阻值，并和完好的ＩＣ进行比较。</span><font face="Times New Roman"><br/>&nbsp;&nbsp;</font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">　　</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><span style="COLOR: red;"><span style="mso-spacerun: yes;">&nbsp;</span></span></font></span><span style="COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">二、在路检测　</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">　这是一种通过万用表检测ＩＣ各引脚在路（ＩＣ在电路中）直流电阻、对地交直流电压以及总工作电流的检测方法。这种方法克服了代换试验法需要有可代换ＩＣ的局限性和拆卸ＩＣ的麻烦，是检测ＩＣ最常用和实用的方法。</span><font face="Times New Roman"><br/>&nbsp;&nbsp;</font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">　　</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><span style="mso-spacerun: yes;"><font face="Times New Roman">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </font></span></span><span style="COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">１．在路直流电阻检测法　</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">　这是一种用万用表欧姆挡，直接在线路板上测量ＩＣ各引脚和外围元件的正反向直流电阻值，并与正常数据相比较，来发现和确定故障的方法。</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><b style="mso-bidi-font-weight: normal;"><span style="COLOR: red;"><span style="mso-spacerun: yes;">&nbsp;</span></span></b></font></span><b style="mso-bidi-font-weight: normal;"><span style="COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">测量时要注意以下三点：　　</span><span lang="EN-US" style="COLOR: red;"><p></p></span></b></p><p></p><p></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>(1)</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">测量前要先断开电源，以免测试时损坏电表和元件。　　</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 10.5pt; mso-char-indent-count: 1.0;"><span lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>(2)</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">万用表电阻挡的内部电压不得大于６Ｖ，量程最好用Ｒ×１００或Ｒ×１ｋ挡。　　</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 10.5pt; mso-char-indent-count: 1.0;"><span lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>(3)</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">测量ＩＣ引脚参数时，要注意测量条件，如被测机型、与ＩＣ相关的电位器的滑动臂位置等，还要考虑外围电路元件的好坏。</span><font face="Times New Roman"><br/>&nbsp;&nbsp;</font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">　　</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><span style="mso-spacerun: yes;"><font face="Times New Roman">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </font></span></span><span style="COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">２．直流工作电压测量法</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">　　这是一种在通电情况下，用万用表直流电压挡对直流供电电压、外围元件的工作电压进行测量；检测ＩＣ各引脚对地直流电压值，并与正常值相比较，进而压缩故障范围，找出损坏的元件。</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><b style="mso-bidi-font-weight: normal;"><span style="COLOR: red;"><span style="mso-spacerun: yes;">&nbsp;</span></span></b></font></span><b style="mso-bidi-font-weight: normal;"><span style="COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">测量时要注意以下八点：　　</span><span lang="EN-US" style="COLOR: red;"><p></p></span></b></p><p></p><p></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>(1)</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">万用表要有足够大的内阻，至少要大于被测电路电阻的１０倍以上，以免造成较大的测量误差。　　</span><span lang="EN-US"><span style="mso-spacerun: yes;"><font face="Times New Roman">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </font></span></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 36.75pt; mso-char-indent-count: 3.5;"><span lang="EN-US"><font face="Times New Roman">(2)</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">通常把各电位器旋到中间位置，如果是电视机，信号源要采用标准彩条信号发生器。　　</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>(3)</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">表笔或探头要采取防滑措施。因任何瞬间短路都容易损坏ＩＣ。可采取如下方法防止表笔滑动：取一段自行车用气门芯套在表笔尖上，并长出表笔尖约０．５ｍｍ左右，这既能使表笔尖良好地与被测试点接触，又能有效防止打滑，即使碰上邻近点也不会短路。　　</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>(4)</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">当测得某一引脚电压与正常值不符时，应根据该引脚电压对ＩＣ正常工作有无重要影响以及其他引脚电压的相应变化进行分析，才能判断ＩＣ的好坏。　　</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>(5)</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">ＩＣ引脚电压会受外围元器件影响。当外围元器件发生漏电、短路、开路或变值时，或外围电路连接的是一个阻值可变的电位器，则电位器滑动臂所处的位置不同，都会使引脚电压发生变化。　　</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;&nbsp; </span>(6)</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">若ＩＣ各引脚电压正常，则一般认为ＩＣ正常；若ＩＣ部分引脚电压异常，则应从偏离正常值最大处入手，检查外围元件有无故障，若无故障，则ＩＣ很可能损坏。　　</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>(7)</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">对于动态接收装置，如电视机，在有无信号时，ＩＣ各引脚电压是不同的。如发现引脚电压不该变化的反而变化大，该随信号大小和可调元件不同位置而变化的反而不变化，就可确定ＩＣ损坏。　　</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;&nbsp; </span>(8)</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">对于多种工作方式的装置，如录像机，在不同工作方式下，ＩＣ各引脚电压也是不同的。</span><font face="Times New Roman"><br/>&nbsp;&nbsp;</font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">　　</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><span style="mso-spacerun: yes;"><font face="Times New Roman">&nbsp;&nbsp;&nbsp;&nbsp; </font></span></span><span style="COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">３．交流工作电压测量法</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">　　为了掌握ＩＣ交流信号的变化情况，可以用带有ｄＢ插孔的万用表对ＩＣ的交流工作电压进行近似测量。检测时万用表置于交流电压挡，正表笔插入ｄＢ插孔；对于无ｄＢ插孔的万用表，需要在正表笔串接一只０．１～０．５μＦ隔直电容。该法适用于工作频率比较低的ＩＣ，如电视机的视频放大级、场扫描电路等。由于这些电路的固有频率不同，波形不同，所以所测的数据是近似值，只能供参考。</span><font face="Times New Roman"><br/>&nbsp;&nbsp;</font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">　　</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><span style="mso-spacerun: yes;"><font face="Times New Roman">&nbsp;&nbsp;&nbsp;&nbsp; </font></span></span><span style="COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">４．总电流测量法</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">　　该法是通过检测ＩＣ电源进线的总电流，来判断ＩＣ好坏的一种方法。由于ＩＣ内部绝大多数为直接耦合，ＩＣ损坏时（如某一个ＰＮ结击穿或开路）会引起后级饱和与截止，使总电流发生变化。所以通过测量总电流的方法可以判断ＩＣ的好坏。也可用测量电源通路中电阻的电压降，用欧姆定律计算出总电流值。</span><font face="Times New Roman"><br/>&nbsp;&nbsp;</font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">　　</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><span style="COLOR: red;"><span style="mso-spacerun: yes;">&nbsp;</span></span></font></span><span style="COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">以上检测方法，各有利弊，在实际应用中最好将各种方法结合起来，灵活运用。</span><span lang="EN-US" style="COLOR: red;"><p></p></span></p><p></p><p></p><p></p><p></p>

[此贴子已经被作者于2007-4-17 0:24:27编辑过]

<p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span class="bw1"><span style="FONT-WEIGHT: normal; COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-size: 10.5pt; mso-bidi-font-weight: bold;">用万用表判别光电耦合器<font color="#000000"></font></span></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span class="bw1"><span style="FONT-WEIGHT: normal; COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-size: 10.5pt; mso-bidi-font-weight: bold;">&nbsp;&nbsp; </span></span><span style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;">用一只指针式万用表即可判别光电耦合器。笔者以四脚型光电耦合器ＰＣ８１７为例，说明其判别方法。</span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;"><br/><font face="Times New Roman">&nbsp;<span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp; </span>&nbsp;&nbsp;&nbsp;</font></span><span style="FONT-SIZE: 10pt; COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;">在光电耦合器内部，包含一只发光二极管和一只光敏三极管。</span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: red; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;"><br/></span><font face="Times New Roman"><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;">&nbsp;&nbsp;&nbsp;<span style="mso-spacerun: yes;">&nbsp; </span></span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: red; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;">&nbsp; </span></font><span style="FONT-SIZE: 10pt; COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;">１．</span><span style="FONT-SIZE: 10pt; COLOR: red; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;"><font face="Times New Roman">
                        </font></span><span style="FONT-SIZE: 10pt; COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;">判断发光二极管的管脚。</span><span style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;"><font face="Times New Roman">
                        </font></span><span style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;">用ＭＦ３０万用表Ｒ</span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;"><font face="Times New Roman">×</font></span><span style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;">１ｋ</span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;"><font face="Times New Roman">Ω</font></span><span style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;">挡，对四只管脚中任意两脚进行正反向测量，如果有一次表针指数为无穷大，但表笔互换后有３０ｋ</span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;"><font face="Times New Roman">Ω</font></span><span style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;">左右的电阻值，此时黑表笔所接的管脚即为发光二极管的正极，红表笔所接的管脚为发光二极管的负极。</span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;"><br/><font face="Times New Roman">&nbsp;&nbsp;<span style="mso-spacerun: yes;">&nbsp;&nbsp; </span>&nbsp;&nbsp;</font></span><span style="FONT-SIZE: 10pt; COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;">２．</span><span style="FONT-SIZE: 10pt; COLOR: red; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;"><font face="Times New Roman">
                        </font></span><span style="FONT-SIZE: 10pt; COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;">判断光敏三极管的集电极与发射极。</span><span style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;"><font face="Times New Roman">
                        </font></span><span style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;">光电耦合器中的光敏三极管通常为ＮＰＮ型，它与普通的ＮＰＮ型硅三极管有许多相似的地方。用万用表Ｒ</span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;"><font face="Times New Roman">×</font></span><span style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;">１０ｋ</span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;"><font face="Times New Roman">Ω</font></span><span style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;">挡，对ＰＣ８１７剩余的两脚进行测量。如果有一次电阻为无穷大，而交换表笔后有２５０ｋ</span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;"><font face="Times New Roman">Ω</font></span><span style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;">左右的电阻值，那么此时黑表笔所接的管脚即为光电三极管的发射极，红表笔所接的管脚则为光电三极管的集电极。</span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;"><br/><font face="Times New Roman">&nbsp;</font></span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: red; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;"><font face="Times New Roman">&nbsp;<span style="mso-spacerun: yes;">&nbsp; </span>&nbsp;&nbsp;</font></span><span style="FONT-SIZE: 10pt; COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;">至此，</span><span style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;">四脚光耦ＰＣ８１７的管脚排列已完全确定，如附图所示。至于多脚型光耦合管的管脚排列，应首先将所有发光二极管的管脚判别出来，然后再确定对应的光敏三极管的管脚。</span><span class="bw1"><span lang="EN-US" style="FONT-WEIGHT: normal; COLOR: red; FONT-FAMILY: ˎ̥; mso-bidi-font-size: 10.5pt; mso-bidi-font-weight: bold;"><p></p></span></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US" style="COLOR: red; mso-bidi-font-size: 10.5pt;"><p><font face="Times New Roman">&nbsp;</font></p></span></b></p>

<p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 26.25pt; mso-char-indent-count: 2.5;"><strong><span style="FONT-WEIGHT: normal; COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-size: 10.5pt; mso-bidi-font-weight: bold;">用万用表检测变压器功率</span></strong><strong><span lang="EN-US" style="FONT-WEIGHT: normal; COLOR: red; FONT-FAMILY: ˎ̥; mso-bidi-font-size: 10.5pt; mso-bidi-font-weight: bold;"><p></p></span></strong></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 26.25pt; mso-char-indent-count: 2.5;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">只用一个万用表是不行的，可以找几个摩托车用的灯泡，根据变压器的输出电压，串联灯泡接入变压器输出端，万用表测量输出端电压，在变压器输出端再继续并联灯泡，发现输出电压明显降低很多时，停止继续并联灯泡，记住电压值。再用万用表测量这时的电流值，记住电流值。电压值</span><span lang="EN-US"><font face="Times New Roman">×</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">电流值＝基本额定功率</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span class="bw1"><span style="FONT-WEIGHT: normal; COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-size: 10.5pt; mso-bidi-font-weight: bold;">万用表与数字的优缺点</span></span><span style="FONT-SIZE: 8pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;">指针式与数字式万用表各有优缺点</span><span lang="EN-US" style="FONT-SIZE: 8pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt;"><font face="Times New Roman">. <p></p></font></span></p><p class="MsoNormal" align="left" style="MARGIN: 0cm 0cm 0pt; TEXT-ALIGN: left; mso-pagination: widow-orphan; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto;"><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">&nbsp;&nbsp;&nbsp; &nbsp;</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">指针万用表是一种平均值式仪表</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">它具有直观</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">形象的读数指示</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.<p></p></font></span></p><p class="MsoNormal" align="left" style="MARGIN: 0cm 0cm 0pt; TEXT-ALIGN: left; mso-pagination: widow-orphan; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto;"><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">&nbsp;&nbsp;&nbsp; &nbsp;(</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">一般读数值与指针摆动角度密切相关</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">,</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">所以很直观</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">).<p></p></font></span></p><p class="MsoNormal" align="left" style="MARGIN: 0cm 0cm 0pt; TEXT-ALIGN: left; mso-pagination: widow-orphan; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto;"><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">&nbsp;&nbsp;&nbsp;<span style="mso-spacerun: yes;">&nbsp; </span>&nbsp;</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">数字万用表是瞬时取样式仪表</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">它采用</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">0.3</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">秒取一次样来显示测量结果</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">有时每次取样结果只是十分相近</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">并不完全相同</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">这对于读取结果就不如指针式方便</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.<p></p></font></span></p><p class="MsoNormal" align="left" style="MARGIN: 0cm 0cm 0pt; TEXT-ALIGN: left; mso-pagination: widow-orphan; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto;"><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">&nbsp;&nbsp;&nbsp;<span style="mso-spacerun: yes;">&nbsp;&nbsp; </span>&nbsp;</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">指针式万用表一般内部没有放大器</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">所以内阻较小</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">比如</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">MF-10</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">型</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">,</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">直流电压灵敏度为</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">100</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">千欧</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">/</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">伏</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">这算是姣姣者了</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.MF-500</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">型的直流电压灵敏度为</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">20</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">千欧</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">/</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">伏</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.<p></p></font></span></p><p class="MsoNormal" align="left" style="MARGIN: 0cm 0cm 0pt; TEXT-ALIGN: left; mso-pagination: widow-orphan; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto;"><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">&nbsp;&nbsp;<span style="mso-spacerun: yes;">&nbsp;&nbsp; </span>&nbsp;&nbsp;</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">数字式万用表由于内部采用了运放电路</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">内阻可以做得很大</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">往往在</span><chmetcnv wst="on" tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="1" unitname="m"><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">1M</font></span></chmetcnv><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">欧或更大</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.(</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">即可以得到更高的灵敏度</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">).</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">这使得对被测电路的影响可以更小</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">测量精度较高</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.<p></p></font></span></p><p class="MsoNormal" align="left" style="MARGIN: 0cm 0cm 0pt; TEXT-ALIGN: left; mso-pagination: widow-orphan; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto;"><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">&nbsp;&nbsp;&nbsp;&nbsp;<span style="mso-spacerun: yes;">&nbsp;&nbsp; </span></font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">指针式万用表由于内阻较小</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">,</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">且多采用分立元件构成分流分压电路</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">所以频率特性是不均匀的</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">(</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">相对数字式来说</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">).</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">而指针式万用表的频率特性相对好一点</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.<p></p></font></span></p><p class="MsoNormal" align="left" style="MARGIN: 0cm 0cm 0pt; TEXT-ALIGN: left; mso-pagination: widow-orphan; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto;"><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">&nbsp;&nbsp;&nbsp;&nbsp;<span style="mso-spacerun: yes;">&nbsp;&nbsp; </span></font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">指针式万用表内部结构简单所以成本较低</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">功能较少</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">维护简单</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">过流过压能力较强</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.<p></p></font></span></p><p class="MsoNormal" align="left" style="MARGIN: 0cm 0cm 0pt; TEXT-ALIGN: left; mso-pagination: widow-orphan; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto;"><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">&nbsp;&nbsp;<span style="mso-spacerun: yes;">&nbsp;&nbsp; </span>&nbsp;&nbsp;</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">数字式万用表内部采用了多种振荡</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">,</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">放大</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">分频</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">保护等电路所以功能较多</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">,</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">比如可以测量温度</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">频率</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">(</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">在一个较低的范围</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">).</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">电容</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">,</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">电感</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">或做信号发生器等等</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.<p></p></font></span></p><p class="MsoNormal" align="left" style="MARGIN: 0cm 0cm 0pt; TEXT-ALIGN: left; mso-pagination: widow-orphan; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto;"><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">&nbsp;&nbsp;&nbsp;<span style="mso-spacerun: yes;">&nbsp;&nbsp; </span>&nbsp;</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">由于内部结构多用集成电路所以过载能力较差</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.(</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">不过现在有些已能自动换档</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">自动保护等</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">但使用较复杂</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">).</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">损坏后一般也不易修复</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.<p></p></font></span></p><p class="MsoNormal" align="left" style="MARGIN: 0cm 0cm 0pt; TEXT-ALIGN: left; mso-pagination: widow-orphan; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto;"><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">&nbsp;&nbsp;&nbsp;<span style="mso-spacerun: yes;">&nbsp;&nbsp; </span>&nbsp;</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">数字式万用表输出电压较低</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">(</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">通常不超过</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">1</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">伏</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">).</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">对于一些电压特性特殊的元件的测试不便</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">(</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">如</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">,</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">可控硅</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">,</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">发光二极管等</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">)<p></p></font></span></p><p class="MsoNormal" align="left" style="MARGIN: 0cm 0cm 0pt; TEXT-ALIGN: left; mso-pagination: widow-orphan; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto;"><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">&nbsp;&nbsp;<span style="mso-spacerun: yes;">&nbsp;&nbsp; </span>&nbsp;&nbsp;</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">指针式万用表输出电压较高</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">,(</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">有</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">10.5</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">伏</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">,12</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">伏等</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">).<p></p></font></span></p><p class="MsoNormal" align="left" style="MARGIN: 0cm 0cm 0pt; TEXT-ALIGN: left; mso-pagination: widow-orphan; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto;"><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">&nbsp;&nbsp;&nbsp;<span style="mso-spacerun: yes;">&nbsp;&nbsp; </span>&nbsp;</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">电流也大</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">(</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">如</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">MF-500*1</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">欧档最大有</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">100</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">毫安左右</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">)</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">可以方便的测试可控硅</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">,</font></span><span style="COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">发光二极管等</span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.<p></p></font></span></p><p class="MsoNormal" align="left" style="MARGIN: 0cm 0cm 0pt; TEXT-ALIGN: left; mso-pagination: widow-orphan; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto;"><span lang="EN-US" style="COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">&nbsp;&nbsp;&nbsp;<span style="mso-spacerun: yes;">&nbsp;&nbsp; </span>&nbsp;</font></span><span style="COLOR: blue; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">对于初学者</span><span lang="EN-US" style="COLOR: blue; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">,</font></span><span style="COLOR: blue; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">应当使用指针式万用表</span><span lang="EN-US" style="COLOR: blue; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">.<p></p></font></span></p><p class="MsoNormal" align="left" style="MARGIN: 0cm 0cm 0pt; TEXT-ALIGN: left; mso-pagination: widow-orphan; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto;"><span lang="EN-US" style="COLOR: blue; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">&nbsp;&nbsp;&nbsp;<span style="mso-spacerun: yes;">&nbsp;&nbsp; </span>&nbsp;</font></span><span style="COLOR: blue; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">对于非初学者</span><span lang="EN-US" style="COLOR: blue; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;"><font face="Times New Roman">,</font></span><span style="COLOR: blue; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">应当使用两种仪表</span><font face="Times New Roman"><span lang="EN-US" style="COLOR: blue; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt;">.</span><span class="bw1"><span lang="EN-US" style="FONT-WEIGHT: normal; COLOR: blue; FONT-FAMILY: ˎ̥; mso-bidi-font-size: 10.5pt; mso-bidi-font-weight: bold;"><p></p></span></span></font></p><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt;"></span>

<p style="TEXT-INDENT: 24pt; mso-char-indent-count: 2.0;"><span class="bw1"><span style="FONT-WEIGHT: normal; COLOR: red; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-size: 10.5pt; mso-bidi-font-weight: bold;">万用表的使用的注意事项</span></span><span class="bw1"><span lang="EN-US" style="FONT-WEIGHT: normal; COLOR: red; FONT-FAMILY: ˎ̥; mso-bidi-font-size: 10.5pt; mso-bidi-font-weight: bold;"><p></p></span></span></p><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-font-kerning: 1.0pt;">（</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt;"><font face="宋体, MS Song">1</font></span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-font-kerning: 1.0pt;">）在使用万用表之前，应先进行</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt;"><font face="宋体, MS Song">“</font></span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-font-kerning: 1.0pt;">机械调零</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt;"><font face="宋体, MS Song">”</font></span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-font-kerning: 1.0pt;">，即在没有被测电量时</span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt;"><font face="宋体, MS Song">
                </font></span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-font-kerning: 1.0pt;">，使万用表指针指在零电压或零电流的位置上。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt;"><br/></span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-font-kerning: 1.0pt;">　　（</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt;"><font face="宋体, MS Song">2</font></span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-font-kerning: 1.0pt;">）在使用万用表过程中，不能用手去接触表笔的金属部分</span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt;"><font face="宋体, MS Song">
                </font></span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-font-kerning: 1.0pt;">，这样一方面可以保证测量的准确，另一方面也可以保证人身安全。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt;"><br/><span style="mso-spacerun: yes;"><font face="宋体, MS Song">&nbsp;&nbsp;&nbsp; </font></span></span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-font-kerning: 1.0pt;">（</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt;"><font face="宋体, MS Song">3</font></span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-font-kerning: 1.0pt;">）在测量某一电量时，不能在测量的同时换档，尤其是在测量高电压或大电流时</span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt;"><font face="宋体, MS Song">
                </font></span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-font-kerning: 1.0pt;">，更应注意。否则，会使万用表毁坏。如需换挡，应先断开表笔，换挡后再去测量。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt;"><br/><span style="mso-spacerun: yes;"><font face="宋体, MS Song">&nbsp;&nbsp;&nbsp; </font></span></span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-font-kerning: 1.0pt;">（</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt;"><font face="宋体, MS Song">4</font></span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-font-kerning: 1.0pt;">）万用表在使用时，必须水平放置，以免造成误差。同时，</span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt;"><font face="宋体, MS Song">
                </font></span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-font-kerning: 1.0pt;">还要注意到避免外界磁场对万用表的影响。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt;"><br/><span style="mso-spacerun: yes;"><font face="宋体, MS Song">&nbsp;&nbsp; </font></span></span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-font-kerning: 1.0pt;">（</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt;"><font face="宋体, MS Song">5</font></span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-font-kerning: 1.0pt;">）万用表使用完毕，应将转换开关置于交流电压的最大挡。如果长期不使用</span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt;"><font face="宋体, MS Song">
                </font></span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-font-kerning: 1.0pt;">，还应将万用表内部的电池取出来，以免电池腐蚀表内其它器件。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt;"><br style="mso-special-character: line-break;"/><br style="mso-special-character: line-break;"/><p style="TEXT-INDENT: 21pt; mso-char-indent-count: 2.0;"><span style="FONT-SIZE: 10.5pt; COLOR: red; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">欧姆挡的使用</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: red; FONT-FAMILY: ˎ̥;"><p></p></span></p><p style="TEXT-INDENT: 21pt; mso-char-indent-count: 2.0;"><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">　一、选择合适的倍率。在欧姆表测量电阻时，应选适当的倍率，使指针指示在中值附近。最好不使用刻度左边三分之一的部分，这部分刻度密集很差。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;"><br/><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">二、使用前要调零。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;"><br/><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">三、不能带电测量。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;"><br/><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">四、被测电阻不能有并联支路。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;"><br/><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">五、测量晶体管、电解电容等有极性元件的等效电阻时，必须注意两支笔的极性。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;"><br/></span><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">六、用万用表不同倍率的欧姆挡测量非线性元件的等效电阻时，测出电阻值是不相同的。这是由于各挡位的中值电阻和满度电流各不相同所造成的，机械表中，一般倍率越小，测出的阻值越小。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;"><p></p></span></p><p style="TEXT-INDENT: 21pt; mso-char-indent-count: 2.0;"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;"><br/></span><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">　　</span><span style="FONT-SIZE: 10.5pt; COLOR: red; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">万用表测直流时</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: red; FONT-FAMILY: ˎ̥;"><p></p></span></p><p style="MARGIN-LEFT: 21pt; mso-para-margin-left: 2.0gd;"><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">一、进行机械调零。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;"><br/></span><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">二、选择合适的量程档位。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;"><br/></span><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">三、使用万用表电流挡测量电流时，应将万用表串联在被子测电路中，因为只有串连接才能使流过电流表的电流与被测支路电流相同</span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;">
                        </span><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">。测量时，应断开被测支路</span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;">
                        </span><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">，将万用表红、黑表笔串接在被断开的两点之间</span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;">
                        </span><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">。特别应注意电流表不能并联接在被子测电路中</span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;">
                        </span><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">，这样做是很危险的，极易使万表烧毁。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;"><br/></span><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">四、注意被测电量极性。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;"><br/></span><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">五、正确使用刻度和读数。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;"><br/></span><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">六、当选取用直流电流的</span><chmetcnv wst="on" tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="2.5" unitname="a"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;">2.5A</span></chmetcnv><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">挡时，万用表红表笔应插在</span><chmetcnv wst="on" tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="2.5" unitname="a"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;">2.5A</span></chmetcnv><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">测量插孔内</span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;">
                        </span><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">，量程开关可以置于直流电流挡的任意量程上。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;"><br/></span><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">七、如果被子测的直流电流大于</span><chmetcnv wst="on" tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="2.5" unitname="a"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;">2.5A</span></chmetcnv><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">，则可将</span><chmetcnv wst="on" tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="2.5" unitname="a"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;">2.5A</span></chmetcnv><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">挡扩展为</span><chmetcnv wst="on" tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="5" unitname="a"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;">5A</span></chmetcnv><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">挡</span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;">
                        </span><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">。方法很简单，使用者可以在</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;">“<chmetcnv wst="on" tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="2.5" unitname="a">2.5A</chmetcnv>”</span><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">插孔和黑表笔插孔之间接入一支</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;">0.24</span><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">欧姆的电阻</span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;">
                        </span><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">，这样该挡位就变成了</span><chmetcnv wst="on" tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="5" unitname="a"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;">5A</span></chmetcnv><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">电流挡了。接入的</span><chmetcnv wst="on" tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="0.24" unitname="a"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;">0.24A</span></chmetcnv><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">电阻应选取用</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;">2W</span><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">以上的线绕电阻</span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;">
                        </span><span style="FONT-SIZE: 10.5pt; COLOR: black; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">，如果功率太小会使之烧毁。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: ˎ̥;"><p></p></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 26.35pt; mso-char-indent-count: 2.5;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US" style="COLOR: red; mso-bidi-font-size: 10.5pt;"><p><font face="Times New Roman">&nbsp;</font></p></span></b></p></span>

<p>再补充一些.也不知会不会重复,重复了请别怪哈.</p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 26.25pt; mso-char-indent-count: 2.5;"><span style="COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">万用表最大的特点</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">是有一个量程转换开关，各中功能就是靠这个开关来切换的。基本上，用</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">A-</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">来表示测直流电流，一般毫安档和安培档各又分几档。</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">V-</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">表示测直流电压，高级点的万用表有毫伏档，电压档也分几档。</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">V~</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">是用来测交流电压的。</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">A~</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">测交流电流。</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;"><p></p></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 26.25pt; mso-char-indent-count: 2.5;"><span lang="EN-US" style="COLOR: red; FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">Ω</span><span style="COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">欧姆档测电阻</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">，对于指针式万用表，每换一次电阻档还要做一次调零。调零就是把万用表的红表笔和黑表笔搭在</span><span style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">
                </span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">一起，然后转动调零钮，使指针指向零的位置。</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">hFE</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">是测量三极管的电流放大系数的，只要把三极管的三个管脚插入万用表面板上对应的孔中，就能测出</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">hFE</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">值。注意</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">PNP</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">、</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">NPN</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">是不同的。</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">
                        <br/><br/><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span style="COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">以下以</span><span lang="EN-US" style="COLOR: red; FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">MF30</span><span style="COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">型万用表为例，</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">说明万用表的读数。第一条刻度线是电阻值指示，最左端是无穷大，右端为零，当中刻度不均匀。电阻档有</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">R×1</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">、</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">R×10</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">、</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">R×100</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">、</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">R×1K</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">、</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">R×10K</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">各档，分别说明刻度的指示再要乘上的倍数，才得到实际的电阻值（单位为欧姆）。</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">
                        <br/><br/><span style="mso-spacerun: yes;">&nbsp;&nbsp; </span><span style="COLOR: red;"><span style="mso-spacerun: yes;">&nbsp;</span></span></span><span style="COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">例</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">如用</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">R×100</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">档测一电阻，指针指示为</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">“<chmetcnv wst="on" tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="10" unitname="”">10”</chmetcnv></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">，那么它的电阻值为</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">10×100=1000</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">，即</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">1K</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">。第二条刻度线是</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">500V</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">档和</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">500mA</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">档共用，需要注意的是电压档、电流档的指示原理不同于电阻档，</span><span style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">
                </span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">例如</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">5V</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">档表示该档只能测量</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">5V</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">以下的电压，</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">500mA</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">档只能测量</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">500mA</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">以下的电流，若是超过量程，就会损坏万用表。</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">
                        <br/><br/><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp; </span></span><b style="mso-bidi-font-weight: normal;"><span style="COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">注意事项：</span></b><span style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">
                </span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">万用表使用时应该水平着放。红表笔插在</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">+</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">孔内，黑表笔插入</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">-</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">孔内。</span><span style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">
                </span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">测试电流就用电流档，而不能误用电压档、电阻挡，其他同理，否则轻则烧万用表内的保险丝，重则损坏表头。事先不知道量程，</span><span style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">
                </span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">就选用最大量程尝试着测量，然后断开测量电路再换档，切不可在线的情况下转换量程。有表针迅速偏转到底的情况，应该立即断开电路，进行检查。</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">
                        <br/><br/><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;&nbsp; </span></span><b style="mso-bidi-font-weight: normal;"><span style="COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">最后还有一个规矩，</span></b><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">就是约定用完后的万用表要把量程开关拨到交流电压最高档，以防别人不慎测量</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">220V</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">市电电压而损坏。记住这个老前辈们留下的优良传统呦！</span><b style="mso-bidi-font-weight: normal;"><span lang="EN-US" style="COLOR: red; mso-bidi-font-size: 10.5pt;"><p></p></span></b></p><p>&nbsp;</p>

<p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 25.85pt; mso-char-indent-count: 2.45;"><b style="mso-bidi-font-weight: normal;"><span style="COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">万用表校准的原理</span></b><b style="mso-bidi-font-weight: normal;"><span lang="EN-US" style="COLOR: red; FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;"><p></p></span></b></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 25.7pt; mso-char-indent-count: 2.45;"><span style="COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">基本原理</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">：当被检测电势与一个已知的，大小相等方向相反的电势构成闭合回路时，电路中因电势平衡而无电流流动，此时就可根据已知电势得知待测电势。</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">
                        <br/></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">做法：</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">
                        <br/><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;&nbsp; </span>1</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">。标准电流流过一个精密电阻箱，你就可以在精密电阻箱上得到对应的很多档准确的电压值。</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">
                        <br/><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;&nbsp; </span>2</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">。将一个精密电阻、一个调电流用的电位器串联到电阻箱和电源构成的回路中，精密电阻</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">→</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">电阻箱</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">→</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">电位器</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">→</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">电源</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">→</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">回到精密电阻，，</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">
                        <br/><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;&nbsp; </span>3</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">。现在测量精密电阻上的电势，同时不能对电流产生影响。做法是将标准电势并到上面（你的</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">200mv</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">），调整电位器（精密电阻上的压降会随之改变），直到由标准电池和精密电阻构成的第二个回路中无电流产生（用检流计测），此时精密电阻上电势（压降）等于标准电势，于是得到标准电流值。假设你的精密电阻是</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">2</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">欧姆，调出的就是</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">100</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">毫安标准电流。</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">
                        <br/><br/><span style="mso-spacerun: yes;">&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">此时你的标准电阻箱如果是</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">1</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">欧姆，那么电阻箱两端的压降是</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">1X100=100</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">毫伏，同理，如果电阻箱是</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">100</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">欧姆，压降就是</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">10</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">伏。你现在可以直接从电阻箱的读数知道它上面的压降了。</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">
                        <br/><br/><span style="mso-spacerun: yes;">&nbsp;&nbsp; </span>4</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">。待较准的万用表一端接电阻箱和电位器连的那端，另一端通过同一检流计接入和精密电阻连接的电阻箱另一端。万用表</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">→</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">电阻箱</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">→</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">检流计</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">→</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">回到万用表，构成第三个回路。</span><span lang="EN-US" style="FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;">
                        <br/><br/></span><span style="COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">注意随时调整电位器，让检流计指零。</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-bidi-font-size: 10.5pt;">此时标准电流不会因为你的万用表接入测量电路而改变，所以测量值是准确的。（如果不调电位器，万用表一接入就会造成分流，标准电流就会改变，测量值不准）</span><b style="mso-bidi-font-weight: normal;"><span lang="EN-US" style="COLOR: red; FONT-FAMILY: Arial; mso-bidi-font-size: 10.5pt;"><p></p></span></b></p>

<p><font size="2"><strong><font color="#ff0000" size="4">使用万用表的注意事项</font></strong></font></p><p class="MsoNormal"><font size="2"><span style="FONT-FAMILY: 宋体;">万用表是比较精密的仪器，如果使用不当，不仅造成测量不准确且极易损坏。但是，只要我们掌握万用表的使用方法和注意事项，谨慎从事，那么万用表就能经久耐用。使用万用表是应注意如下事项：</span></font></p><p class="MsoNormal" style="MARGIN-LEFT: 42pt; TEXT-INDENT: -21pt;"><font size="2"><span lang="EN-US" style="FONT-FAMILY: Wingdings;">l<span style="FONT-WEIGHT: normal; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; FONT-VARIANT: normal;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span style="FONT-FAMILY: 宋体;">测量电流与电压不能旋错档位。如果误将电阻档或电流档去测电压，就极易烧坏电表。万用表不用时，最好将档位旋至交流电压最高档，避免因使用不当而损坏。</span></font></p><p class="MsoNormal" style="MARGIN-LEFT: 42pt; TEXT-INDENT: -21pt;"><font size="2"><span lang="EN-US" style="FONT-FAMILY: Wingdings;">l<span style="FONT-WEIGHT: normal; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; FONT-VARIANT: normal;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span style="FONT-FAMILY: 宋体;">测量直流电压和直流电流时，注意“</span><span lang="EN-US">+</span><span style="FONT-FAMILY: 宋体;">”“</span><span lang="EN-US">-</span><span style="FONT-FAMILY: 宋体;">”极性，不要接错。如发现指针开反转，既应立即调换表棒，以免损坏指针及表头。</span></font></p><p class="MsoNormal" style="MARGIN-LEFT: 42pt; TEXT-INDENT: -21pt;"><font size="2"><span lang="EN-US" style="FONT-FAMILY: Wingdings;">l<span style="FONT-WEIGHT: normal; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; FONT-VARIANT: normal;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span style="FONT-FAMILY: 宋体;">如果不知道被测电压或电流的大小，应先用最高档，而后再选用合适的档位来测试，以免表针偏转过度而损坏表头。所选用的档位愈靠近被测值，测量的数值就愈准确。</span></font></p><p class="MsoNormal" style="MARGIN-LEFT: 42pt; TEXT-INDENT: -21pt;"><font size="2"><span lang="EN-US" style="FONT-FAMILY: Wingdings;">l<span style="FONT-WEIGHT: normal; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; FONT-VARIANT: normal;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span style="FONT-FAMILY: 宋体;">测量电阻时，不要用手触及元件的裸体的两端（或两支表棒的金属部分），以免人体电阻与被测电阻并联，使测量结果不准确。</span></font></p><p class="MsoNormal" style="MARGIN-LEFT: 42pt; TEXT-INDENT: -21pt;"><font size="2"><span lang="EN-US" style="FONT-FAMILY: Wingdings;">l<span style="FONT-WEIGHT: normal; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; FONT-VARIANT: normal;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span style="FONT-FAMILY: 宋体;">测量电阻时，如将两支表棒短接，调“零欧姆”旋钮至最大，指针仍然达不到</span><span lang="EN-US">0</span><span style="FONT-FAMILY: 宋体;">点，这种现象通常是由于表内电池电压不足造成的，应换上新电池方能准确测量。</span></font></p><p class="MsoNormal" style="MARGIN-LEFT: 42pt; TEXT-INDENT: -21pt;"><font size="2"><span lang="EN-US" style="FONT-FAMILY: Wingdings;">l<span style="FONT-WEIGHT: normal; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; FONT-VARIANT: normal;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span style="FONT-FAMILY: 宋体;">万用表不用时，不要旋在电阻档，因为内有电池，如不小心易使两根表棒相碰短路，不仅耗费电池，严重时甚至会损坏表头。</span></font>
        </p><p class="MsoNormal" style="MARGIN-LEFT: 42pt; TEXT-INDENT: -21pt;">&nbsp;</p><p class="MsoNormal" style="MARGIN-LEFT: 42pt; TEXT-INDENT: -21pt;">我在收集此类文章时，由于我本人的技术还不够专业（我业务出身），所于没有好好的整理一下，本来还有一部份介绍的，我不知会不会重复，也就不在这上面啰嗦了。有兴趣了解的朋友可以留下邮箱，我一定发给你。谢谢支持，请朋友们给顶起来，给雄起哈</p>

谢谢了！好多知识我又巩固了！

好 顶

学习下

学习学习

xue xi

<p>学了</p>

学习~

<p>又学到。。。准备实践看看</p>

<p>还是有点迷糊~</p>
<p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 能不能在清楚点~</p>
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<p><a href="http://www.hnznh.com">www.hnznh.com</a></p>